Known optical fiber connectors include housings made of resin, fitted or integrally formed with ferrules. FIGS. 1a and 1b show optical fiber connector 50 comprising housing 51 made of resin and having integrally formed ferrules 52. Housing 51 further comprises metallic claws 55 for fixing optical fibers F. The metallic claws are generally U-shaped, as seen in FIG. 1b. In this type of device, each optical fiber F is stripped of coating c adjacent its end, thereby exposing fiber core f. Fiber F is then inserted into housing 51 through insertion paths 53, so that fiber core f fits into a corresponding ferrule 52. Insertion paths 53 of housing 51 are provided with slits 54 into which fixing claws 55 are edgewise inserted so as to engage the fiber. Edge portions 55a of fixing claws 55 are thereby pressed against coating c of optical fiber F, thereby fixing it in connector housing 51. By this method, approximately 80N of fixing force can be obtained. However, this force is not sufficient for vehicle applications, where at least 100N is required for such connectors.
FIG. 2 shows another known optical fiber connector 60 comprising a connector housing 61 made of resin and enclosing metallic ferrules 62. Stop 63 prevents ferrules 62 from disengaging. Spring 64 urges ferrules 62 towards the end of the connector housing. Protective cover 65 protects the insertion section where optical fiber F is introduced into connector housing 61.
Ferrules 62 comprise core holder 62a, which has a comparatively small inner diameter and through which fiber core f of the optical fiber F is inserted, coated-portion holder 62b, which has a comparatively large inner diameter and through which coated part c of the optical fiber is inserted, and flange 62c projecting radially outwardly at the periphery between core holder 62a and coated-portion holder 62b. Flanges 62c form abutment faces for spring 64.
To fix optical fiber F to connector housing 61, the end of coated part c of each fiber F is stripped, so that fiber core f is exposed; this end is inserted into ferrule 62, so that coated part c of optical fiber F is frictionally retained by holding part 62b, then springs 64 are inserted into the peripheral area of holding part 62b.
After they have been joined, the fiber end and ferrule 62 are inserted into connector housing 61 so that stop 63 causes springs 64 to press against flange 62c of ferrule 62. When viewed in a lateral cross-section, the inner surface of connector housing 61 presents shoulder 61a. When ferrule 62 is held in connector housing 61, flange 62c is urged against shoulder 61a, thereby insuring the fixing of each optical fiber F. Coating c of fiber F is crimped by holding part 62b of ferrule 62. While this method can provide a fixing force in excess of 100N, it requires precision metal-forming of the ferrules. This leads not only to higher ferrule production costs, but also to a need for other parts, such as springs 64 etc. resulting in further increased costs compared to the optical fiber connector shown in FIGS. 1a and 1b.